1. Field of the Invention
The invention relates to a terminal block, a method of manufacturing or producing it and a nut.
2. Description of the Related Art
Japanese Unexamined patent publication No. 2008-98007, discloses a terminal block for electrically connecting conductors, such as busbars, extending from electrical devices, such as a motor and an inverter. Conductors of the respective electrical devices are placed one above another on nuts insert molded into a resin terminal block main body. Bolts then are tightened into the nuts to fasten and electrically connect the conductors.
The electrical devices generally generate heat and the conductors become hot. Thus, a metal heat sink is arranged below the nuts via a flat plate-shaped insulating member made of synthetic resin. Thus, heat transferred from the conductors to the nuts is transferred to the heat sink via the insulating member and is radiated from the heat sink. The conductors are placed on fastening surfaces of the terminal block. The fastening surfaces are pressed from above by a cut-off part of a mold during the insert molding process to achieve a resin cut-off that prevents the resin from covering the fastening surfaces.
Pressing forces exerted by the resin cut-off parts are distributed over the entire fastening surfaces to reduce contact pressures of the resin cut-off parts acting on the fastening surfaces. However, small clearances may be formed at parts of boundaries between the resin cut-off parts and the fastening surfaces. The resin flows into these clearances and is cured there to produce resin films on the fastening surfaces that prevent the conductors and the nuts from being held in direct contact. This absence of direct contact reduces heat-transfer efficiency and heat radiation performance of the terminal block. Pressing forces of the resin cut-off parts can be increased to cut off the resin more reliably. However, higher pressing forces may fracture the insulating member or damage the fastening surfaces to reduce contact areas with the busbars.
The invention was completed in view of the above situation and an object thereof is to improve heat radiation performance of a terminal block.